EXHAUST

[2001lodown]

Hi everyone just wanted to know if anyone had thier exhaust system replaced on thier 2001 to 2003 replaced before. I bought my 01 QX4 last sept 09, now the exhaust system is goig on me . I can hear the heat shields and i think the front collector pipe or manifold is rattling , but anyway it need to be taken care of . So if any of you guys with a 2001 to 2003 QX4 have replaced your exhaust system i could use some input on if i should get a stock replacement or just get a custom bent system .

[Pwnin O'Brien]

Check out the following thread, it should help you out some on making a decision...

zerothread?id=448373

[fastpathy35]

I replaced all mine,with aftermarket. Im not sure if thats what you were asking about. I also removed all the heat sheilds as i had the rattle problem also. I paid $300 for dual in dual out flowmaster super 40 series. Its a tad loud at times, but sounds awsome IMO. Some say that you lose the low end with the duals but ive capped one side off ( yes its an open chamber muffler in all) and i did notice a loss in power going over the mountain. It downshifted much more with just one pipe. I have a video on youtube of my exhaust. Ii was just toying, but if you want something more specific i can make another video.

[sixty4]

I got a bosal exhaust have been very happy with it and it has a good sound too.

[2001lodown]

looks like its gonna be the bosal system from after the cat converters back , i checked at Napa its gonna run me like around $380 to 400 for the muffler and resonator . thanks yall for the replies and suggestions.

[Innovazn]

Hey Pwnin, seeing as you know a bit now... im still CONFUSED i want to get an exhaust.... being Canadian i need the cats.... I wanna take everything BEHIND the cats out and do custom exhaust. Deciding on the muffler..... want something that will turn heads... im not too worried about the police either (got nothing to hide and i know the higher ups since i work closely with them) The resonator... im a retard... WTF IS IT ?!!?

[Pwnin O'Brien]

Hey Pwnin, seeing as you know a bit now... im still CONFUSED i want to get an exhaust.... being Canadian i need the cats.... I wanna take everything BEHIND the cats out and do custom exhaust. Deciding on the muffler..... want something that will turn heads... im not too worried about the police either (got nothing to hide and i know the higher ups since i work closely with them) The resonator... im a retard... WTF IS IT ?!!?

Ok, so your car has two resonators. Each one is located right after the downpipe under the driver and passenger seats. Here's a good explanation of what a resonator does from wakopedia (the forum automatically changes the name to wakopedia, I don't know why)...

"Resonators, also known as Helmholtz resonators are sections of exhaust pipe that expand to a larger diameter and allow the sound waves to reflect off the walls and cancel out. Resonators are mostly used to reduce raspiness and popping. Resonators are similar to an Expansion chamber, only for 4 stroke engines. They do not produce much back pressure.

Many North-American cars (and possibly cars in other parts of the world) made since the early to mid 1990's can have up to 3 distinct (but similar looking) exhaust components downstream from the catalytic converter(s). Each of these components may be called resonators or mufflers. Usually only the last component is the actual muffler, and the other components are the resonators."

So it is almost a muffler, but it reduces raspiness and popping (or that backfiring noise). In other words, it will help your new exhaust NOT sound like a Honda Civic with a fart can. The good new is that the resonators do not create much backpressure, so they don't choke the system. I highly recommend a Magnaflow high-flow muffler and your EGV's will at least be doubled.

[Innovazn]

Ok, so your car has two resonators. Each one is located right after the downpipe under the driver and passenger seats. Here's a good explanation of what a resonator does from wakopedia (the forum automatically changes the name to wakopedia, I don't know why)...

"Resonators, also known as Helmholtz resonators are sections of exhaust pipe that expand to a larger diameter and allow the sound waves to reflect off the walls and cancel out. Resonators are mostly used to reduce raspiness and popping. Resonators are similar to an Expansion chamber, only for 4 stroke engines. They do not produce much back pressure.

Many North-American cars (and possibly cars in other parts of the world) made since the early to mid 1990's can have up to 3 distinct (but similar looking) exhaust components downstream from the catalytic converter(s). Each of these components may be called resonators or mufflers. Usually only the last component is the actual muffler, and the other components are the resonators."

So it is almost a muffler, but it reduces raspiness and popping (or that backfiring noise). In other words, it will help your new exhaust NOT sound like a Honda Civic with a fart can. The good new is that the resonators do not create much backpressure, so they don't choke the system. I highly recommend a Magnaflow high-flow muffler and your EGV's will at least be doubled.

... ok if those are "resonators" why the hell is everyone calling those cats? youre takling about the piping coming from the manifolds right? cuz according to smart Nissan we have "4" cats but only the 2 in the front under the driver/pass seat are the cats and the back 2 are resonators right? or am i reversed?

[Pwnin O'Brien]

... ok if those are "resonators" why the hell is everyone calling those cats? youre takling about the piping coming from the manifolds right? cuz according to smart Nissan we have "4" cats but only the 2 in the front under the driver/pass seat are the cats and the back 2 are resonators right? or am i reversed?

If you call your Nissan dealership and talk to a tech, they will tell you the following: your vehicle has two catalytic converters, they are bolted directly to the exhaust manifolds and then after those are the resonators (one for each side). Then there is the muffler (the large 2-into-1 muffler) and then there is the post muffler (the small muffler that hangs down from the back of your vehicle).

When you replace the exhaust you should remove the muffler and post muffler to put in a high-flow muffler (either a dual-in/dual-out or two separate mufflers like I have) in the mufflers place. You can also replace the resonators with a new pair (Hushpower makes a nice stainless set for pretty cheap), or you could do a resonator delete also if desired and just run from the catalytic converters to the new muffler.

[Innovazn]

If you call your Nissan dealership and talk to a tech, they will tell you the following: your vehicle has two catalytic converters, they are bolted directly to the exhaust manifolds and then after those are the resonators (one for each side). Then there is the muffler (the large 2-into-1 muffler) and then there is the post muffler (the small muffler that hangs down from the back of your vehicle).

When you replace the exhaust you should remove the muffler and post muffler to put in a high-flow muffler (either a dual-in/dual-out or two separate mufflers like I have) in the mufflers place. You can also replace the resonators with a new pair (Hushpower makes a nice stainless set for pretty cheap), or you could do a resonator delete also if desired and just run from the catalytic converters to the new muffler.

what would be the smarter idea? keeping the resonators i would assume... i want my car sounding loud with a low grumble. i just absolutely LOVE rumble... but forsome reason hate the small cars with their screaming whines

[2001lodown]

i have to admit with my exhaust system right now with a bad ress and muffler sounds awsome but a major loss of acceleration

[Pwnin O'Brien]

what would be the smarter idea? keeping the resonators i would assume... i want my car sounding loud with a low grumble. i just absolutely LOVE rumble... but forsome reason hate the small cars with their screaming whines

Therein lies the problem, with a 6cyl. you really can't get the deep rumble like an 8cyl. with an aftermarket exhaust. I would definitely recommend keeping the resonators or replacing them with some aftermarket ones. To get as close to rumble as possible you would probably need to use a chambered muffler like a Flowmaster or something of the sort. Those are geared more towards sound than performance and longevity. They aren't stainless steel and they can lower EGV's but I think they will produce the sound you're looking for.

[2001lodown]

on the cardomain sites i've seen some nice exhaust systems on qx4 but i'm not willling to loose my spare tire to have a nice looking muffler tips, although nissan should of upgraded the system abit through out the later years of the pathfinder and qx4

[sicwitit]

instead of resonators, why not use x pipes? they are lighter, and cause a similar effect? if you did 2 x pipes downstream of the cats, and pre muffler, it should make for an interesting exhaust sound.

[Pwnin O'Brien]

instead of resonators, why not use x pipes? they are lighter, and cause a similar effect? if you did 2 x pipes downstream of the cats, and pre muffler, it should make for an interesting exhaust sound.

I actually thought of going this route, however, given the awkward exhaust setup and the lack of space under the vehicle it really wasn't feasible. The only place to put the X-pipe would be right before the muffler, but there isn't really any space there either. The only other way to incorporate an X-pipe would be to run the exhaust lower that the current setup (making it visible from the side of the vehicle) but that isn't really a great idea since it will be more vulnerable to rocks/curbs/etc.

Here's a link to the stainless steel Hushpower resonator I was talking about before. It's pretty cheap and it should outlast the vehicle...

http://www.summitracing.com/pa...pe=10

[Innovazn]

Chances are im going to just replace my cat and resonators and simply replace the muffler... my coworker is getting his old muffler ripped out of his 4runner and selling it off to me. besides that... should i do anything else if i want to keep everything where it is? i dont want to lose any acceleration or power... expand my existing pipes maybe?